Ctrl-a Ctrl-c    Create new screen
Ctrl-a w         List screens
Ctrl-a S         Split screens into 2 windows
Ctrl-a n         Next screen
Ctrl-a Tab       Toggle to next window
Ctrl-a X         Destroy window
Ctrl-a Ctrl-a    Switch to the last window displayed
Ctrl-a {n}       Switch to window n
Ctrl-a "         Display all windows for visual selection
Ctrl-a d         Detach the screen session
Ctrl-a D D       Power detach: sends HANGUP to parent process
                 of screen
Ctrl-a x
Ctrl-a Ctrl-x    Call a screenlock program; Warning: Lock is 
                 void when screen has no password and the shells
                 are unlocked.
Ctrl-a *         Shows a tabular listing of all currently 
                 connected user front-ends (displays)

To reattach screen session: screen -r

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* GNU Screen Manual - http://www.gnu.org/software/screen/manual/